Method getAbsoluteColumnIndex

kernel/linear_algebra/Minor.cc:149–179

}

int MinorKey::getAbsoluteColumnIndex(const int i) const
{
  /* This method is to return the absolute (0-based) index of the i-th
     column encoded in \a this.
     Example: bit-pattern of columns: "10010001101", i = 3:
        This should yield the 0-based absolute index of the 3-rd bit
        (counted from the right), i.e. 7. */

  int matchedBits = -1; /* counter for matched bits; this needs to reach i,
                           then we're done */
  for (int block = 0; block < getNumberOfColumnBlocks(); block ++)
  {
    /* start with lowest bits, i.e. in block No. 0 */
    /* the bits in this block of 32 bits: */
    unsigned int blockBits = getColumnKey(block);
    unsigned int shiftedBit = 1;
    int exponent = 0;
    /* The invariant "shiftedBit = 2^exponent" will hold throughout the
       entire while loop. */
    while (exponent < 32)
    {
      if (shiftedBit & blockBits) matchedBits++;
      if (matchedBits == i) return exponent + (32 * block);
      shiftedBit = shiftedBit << 1;
      exponent++;
    }
  }
  /* We should never reach this line of code. */
  assume(false);
  return -1;
}

void MinorKey::getAbsoluteRowIndices(int* const target) const
{